Control system



, 1,614,146 Jan. 1927' 's. w. MULLER 0011111011 SYSTEM Filed Feb. 27.1926 I 3 I Z 5 "an; n;

IhVentOri Gustav W. Muller;

His Attorney.

Patent'e d Jan.- 11, 1927.

UNITED STATES PA ENT OFFICE.

GUSTAV W. MULLER, OF CEABlZ-OTTENBUBG, GERMANY, ASSIGNOR T GENERAL ELEC-TRIO COMPANY, CORPORATION OF NEW YORK. I

cou'rnon sYsrnM.

Application med February 27, 1926, SerialNo. 91,216, and in GermanyMarch 28, 1925.

M invention relates to systems for controlling the operation of amercury arc recconverter for transmitting current between alternatingand direct current circuits. This arrangement has the disadvantage thatoverloading of the rectifier is likely to occur if the alternatingcurrent circuit is for any reason successively deenergized andenergized. In accordance with my invention,

this disadvantage is avoided by .the provi- 2 sion" of means whichoperate to'initiate the transmission of current through the rectifieronly when the converter has attained a predetermined electricalcondition.

My invention will be better understood from the following 'descri tionwhen considered in connection with t e accompanying drawing and itsscope will be pointed out in the appended claims.

The drawing shows a direct current cir-' cuit 1 and an alternatingcurrent circuit 2 -which are interconnected through a rotary converter 3and a rectifier 4 controlled accordance with my invention.

The converter 3: is connected to the alternating currentcircuit 2through slip rings 5 and to the direct current circuit 1 through brushes6. The rectifier 4 comprises anodes 7 which are connected to thesecondary terminals of a transformer 8, a cathode 9 which is connectedto one'side of the direct current circuit 1 through a protective deviceshown as a fuse 10 and a meter shunt 11, exciting electrodes 12 to whichvoltage is applied through a transformer 13, and a starting electrode 14which is connected to a winding .of the transformer '13 through a switch15. The other end of this winding is connected to one of the'excitingelectrodes. Any suitable means such as 1nd ctance devices connectedeither in the exciting electrode leads 'loadin or in the cathode lead ofthe exciting circuit, a transformer having a high reactance or the likemay be utilized to insure continuity of the exciting arc. A relay switch16 biased to its open position by a spring 17 is provided with anoperating coil 18 which is connected to the direct current circuit 1 andthe brushes 6 of. the rotary converter 3.

The rotary converter 3 and rectifier 4 have been shown as located indifferent substations. It will be apparent that the benefits of myinvention are notlimited to this arrangement.

When no voltage. is applied to the alternating current circuit 2, therelay switch 16 is maintained in its open position by the circuit 2, therelay switch 16 doesnot close until the rotary converter is operatingand its direct current voltage has attained a value at which there is nodanger of overthe rectifier; As soonas this voltage is attained,however, therelay is operated to its closed position, the are of 'thestarting electrode is taken up by the exciting electrodes and therectifier 4:, assumes its proper share of theload. If the alternatingcurrent circuit 3 is deenergized and subsequently energized therectifier is thus protected against overload and blowing of the fuse 10is avoided.

The embodiment of the invention illustrated and described herein hasbeen selectedfor the purpose of clearlysetting forth the principlesinvolved. It will be apparent,

however, that the invention issusceptible spring 17. Upontheenergization of the of being modified to meet the different con- Iditions encountered ,in its. use a d I therefore aim to cover b the appeded claims. all modifications wit in the true spirit and scope of myinvention,

What I claim as new and desire to secure by Letters Patent of the UnitedStates is 1. The combination of a direct current circuit, a mercuryarc-rectifier providedwith an anode and cathode co ected to'said directcurrent circuit and with an excitation circuit for maintaining the arcof said rectifier an electrigil machine connected to said direct currentcircuit, and means for controlling the connections of said excitationcircuit in accordance with an electrical condition of said machine.

I 2. The combination of direct and alternating current circuits, atrectifier provided with an anode and cathode for transmitting currentbetween said alternating and direct current circuits and with anexcitation circuit for maintaining the arc of said rectifier,

an electrical machine connected between said 1 In witness whereof, Ihave hereunto set 15 my hand this 8th day of February, 1926.

GUSTAV W. MULLER.

